1. Technical Field of the Invention
The present invention relates generally to a method and system for processing email on a wireless device at times when email service to such device is otherwise not available. More particularly, the present invention provides for backup service to a wireless device during an outage, notifies users that alternative access is available to said email, and restores messages received during the outage into the users' original email system to maintain the integrity and continuity of the email file.
2. Background of the Invention
Individuals and companies are increasingly relying on wireless devices for the seamless delivery of email. Such devices provide users with access to email in a mobile environment. However, most wireless devices are dependent for their operation on the underlying health of the company's corporate email system as well as the wireless hardware and software platforms, such as the Blackberry Enterprise Server (BES), Microsoft PocketPC, or others, necessary to synchronize the wireless capabilities together with the corporate email system. If either the company's corporate email system is out of service, or the hardware or software connections are out of service, the wireless device will be unable to receive email messages.
To provide users with continuous service in the event of an outage, a company may elect to replicate its entire email system, such as a Microsoft Exchange database, in a remote datacenter on hardware similar to that owned by the company. Because of the complexity of such system, such as Microsoft's Exchange architecture, replication strategies have focused on real-time database replication of disks at the byte level or, alternatively, on transferring offline database backups on a server-by-server basis.
Even in cases where a company implements complete replication of its databases, it would not be uncommon for there to be gaps in email continuity due to, for example, database corruption, the presence of viruses, denial of service attacks, security breaches and other factors. Some of the most often cited problems with replication are:                1. High Cost. The cost involved in replication can be staggering. In order to implement an effective replication system, the company must purchase third party replication software, acquire network bandwidth, secure server capacity, retain administrative support and then monitor each of these systems.        2. Replication of Only a Subset of the Servers. As a result of the costs inherent in providing a replicated database, such as, for example, the cost of hardware, software, bandwidth and support personnel, it is common for only a few of the most critical servers to be replicated.        3. Database Corruption. Because replication technology by its very nature mirrors the files from one server onto another, a corrupt file on the original server will be mirrored in its corrupt form on the backup server. There is currently no efficient means for preventing the mirroring of corrupt files.        4. Incapacitation Due to Virus. Similarly, if a virus occurs in a file on the original server, it will be transported to the second server. Server corruption due to viruses can cause email outages for days.        5. Transactional Inconsistency. Because replication solutions typically perform byte-level replication of the disks, they do not provide integrity for the Exchange transaction boundaries. For example, a single transaction on Microsoft Exchange may consist of ten sequential writes to the disk. If the replication software has only replicated eight of those ten at the time of an outage, then the backup will be incomplete, resulting in a corrupt file which may fail to mount.        6. No Vendor-Supported Replication Solution. Currently no system that replicates systems like the Microsoft Exchange database is readily available at an economical price.        7. Complexity of Replication. The complexity of making an efficient, effective replication solution causes the system to be more prone to failure and thereby require greater resources to maintain.        
For all of these reasons the existing technology fails to provide an adequate method for processing email to a wireless device during an outage. There is a need, therefore, for an improved method and system for providing email messages to a wireless device during an outage.